1. Field of the Invention
This invention relates to the upgrading of hydrocarbon oils, e.g., solvent refined automotive oils to oils of turbine quality by treating with an acidified sorbent. Treatment results in the effective removal of polar compounds, e.g., nitrogenous compounds, normally present in such oils and in improved oxidation stability of the oil.
2. Description of the Prior Art
It is known that undesirable nitrogen compounds may be removed from hydrocarbon oils by passing the oil through alumina, bauxite and the like; U.S. 2,384,315. Also, that denitrification of hydrocarbon oils can be accomplished by treatment with a silica/alumina catalyst promoted with fluorine; U.S. Pat. No. 3,014,860. Further, heavy residual hydrocarbon stocks can be upgraded by dispersion in a solvent mixture of methyl ethers and thereafter catalytically cracked by, for example, a zeolitic cracking catalyst; U.S. Pat. No. 3,966,586.
However, mere removal of nitrogen compounds from hydrocarbon oils is not sufficient to upgrade automotive quality oil to turbine quality nor is catalytic cracking a viable means for upgrading refined hydrocarbon base stock to turbine quality oil.